I'm cross-posting here because while this isn't technically a new house, it virtually is. We've raised the house 10', and we're more than doubling the size, and I know there are some knowledgeable architects and builders here.

We're GC'ing a huge addition (more than doubling) and
renovation, including raising our existing house 10'. Our existing house
is a ranch house - a rectangle - with 2x6 rafters.
One side of the house is being extended 11 feet. And both sides of the
house are having additions built on the back - making a U shaped house.

We had plans designed by an engineer, which is required here since we're in a hurricane zone.

The plans call for 2x6 rafters on the side extension - to match the
current rafters in the house - that makes sense. The plans call for 2x8
rafters on the additions. Our framers don't know
how to handle where the valleys are. The lead guy (LG) told me that
doing a normal
bird's mouth on the 2x8 rafters will cause the new roof to be higher on
the top plate than the existing roof is, and where they meet in the
valley there would be a height difference, which wouldn't work. That all
makes sense to me. Then LG told me that they would cut a deeper bird's
mouth in the 2x8 rafters. He was proposing to notch such that it was
only as high above the bird's mouth as a 2x6 rafter is.
I told him I don't think that is allowed, and then I checked the code
and it says you can't notch bigger than 1/4 of the depth. On top of
which you would effectively be making the rafter a 2x6 and if the
engineer had wanted 2x6 he would've specified them.

I've tried to reach my engineer but he hasn't called me back. Soon the
framers are going to run out of other work (which I told them to do for
now while I try to get an answer), and I really need to understand how
the two roofs can meet in the valleys.

Can anyone help? Including maybe suggesting other sites where I can find help?

Thanks!

Alice